This invention concerns improvements made to opening and closing devices for wallet or portfolio-type blowing or stretching-blowing molds that can be used, in particular, for the manufacture of plastic containers such as bottles, flasks, etc., the mold comprising two half-molds pressed against each other in the closed position of the mold.
The invention is applicable to molding configurations in which the half-molds are mounted directly so as to rotate on a common swivel pin, and to molding configurations more frequently used because of their ease of use, in which the half-molds are detachably joined to respective supports, which are in turn mounted so as to rotate on the common swivel pin. To simplify the explanations provided, use will be made hereinafter only of the term "half-mold" it being understood that the half-mold alone or the half-mold and its base will be meant, depending on the configuration in which the invention will be embodied.
In molding equipment such as that designed for the manufacture of plastic containers, of the type incorporating, for example, several associated molds on a revolving plate or turret, the various movements required for the operation of the molds are controlled by cam and motion transmission mechanisms. This is especially true as regards the control of the opening and closing of the molds.
Numerous mold opening and closing devices are known, in particular that described in commonly assigned French Patent No. 2,653,058, which, by virtue of its operating principle, proves entirely satisfactory.